Employers routinely inquire into whether prospective hires would perform on the job as promised.

In New York City this year, the voters are collectively hiring a whole new team of citywide elected officials to serve them in different roles. Former Gov. Eliot Spitzer, running for comptroller, seems to require a particular kind of vetting.

Nobody seems to doubt his intellectual capacity or whether he's in sync with the progressive tilt of a Democratic primary. The questions involve his conduct -- not as private citizen but as public actor.

Lloyd Constantine was a mentor, aide and friend of Spitzer's long before the younger man was governor. Constantine wrote a book called "Journal of the Plague Year" that Spitzer -- barely two years after his downfall -- blasted with lawyerly sanctimony in 2010 as "self-serving," "largely inaccurate" and a "breach of trust." Even then, the ex-governor wasn't too humbled by events to launch an accusatory attack on a disillusioned ally.

And yet Constantine, when contacted this week, expressed support for Spitzer's attempted comeback. He lives in Manhattan and told reporters he was going out to find a Spitzer qualifying petition to sign. During the governorship, he said, Spitzer "knew he was a marked man, he knew it was just a matter of when it would be revealed, and he took office knowing there was a gun to his head."

"It's very hard for the governor to function well knowing that he could go down at any second," Constantine said in remarks first published in the Albany Times Union. "If he's clear of all the things he was engaged in, and I know that he is, I think he'll be an extraordinarily fine comptroller."

Another ex-aide with whom Spitzer fell out, who didn't want to be identified, said he believes Spitzer's behavior of late has been "pretty solid" as opposed to the "steamroller" episodes he displayed while in power. The ex-aide's analysis: "I'd say he's bored. Government service was his passion. He's desperate to prove himself again."

From across the partisan divide, however, Republican state chairman Ed Cox asked Thursday: "How can a politician for whom power is a thrilling end unto itself be trusted with more than a hundred billion dollars of pension funds? He can't.

"He misused the powers of his offices to 'steamroll' legitimate political opposition, and acted with calculated hypocrisy, signing tougher penalties into law for the very crimes he was committing."

Politics is just one business, of course, where ruthlessness can be a character reference and hypocrisies are inevitable. But a prospective public servant's ability to act sensibly also is worth considering.

The fact that Spitzer jumped into this primary race at the last possible moment, and is scrambling with paid help to gather petition signatures, has been interpreted by detractors -- including Stringer supporters -- as a sign of impulsiveness rather than planning. Spitzer also said he didn't take polls first -- which can be considered a sign of independent thinking, stealth, thin planning or all three.

For voters, the Spitzer comeback may hinge on whether they believe a man who fiercely lectured others while trysting with prostitutes -- on trips with state troopers, no less -- has gone in five years from self-destructive to self-controlled.

Or to tweak a favorite 1990s political saying: It's the stability, stupid.